12 Dyeing 5.4 Fastness Wash Fastness : a constant problem. THE CAUSES ?High surface area, means a greater amount of surface dye present.Weight Reduced fibres have oligomer residues that can reduce fastness.Weight Reduced fibres have a rough surface that can act as a store for oligomer and surface dye.WR on delusted fibres leave pores, that act as reservoirs of surface dye.Spandex Microfibre may have silicone residues that reduce fastness.THE REMEDIES ?A very effective wash after Weight Reduction is essential.A very effective high temperature Reduction Clear and wash is essential.A double Reduction Clear may be required.Use of wetting, penetrating and dispersing auxiliaries in both WR wash and RC.

15 NEARGAL LS-PA with acid dyes.Dyeing 6Conjugates :With certain types ofconjugate filament….The compliment or core polymer fibrils may “grin” throughthe shade, creating a streaky, speckled and uneven look.This mainly occurs where :- the compliment fibril is only shocked (by swelling or physicalcracking) rather than dissolving.- the complimentary fibril is a major part.- the conjugate microfibre is a major component of the fabric.- the nylon component is not structurally covered by polyester.Regain solidity of shade by overdyeing with acid dyes.NEARGAL LS-PA with acid dyes.